The purpose of the proposed effort is to continue the development of low cost, high performance ACR-NEMA interface technology begun in the phase I effort. This phase II effort will result in the development of a single board ACR-NEMA/FDDI Network Interface Unit (NIU) and the evaluation of this unit in a prototype medical imaging network. The near term demonstration of a medical imaging network which incorporates such an NIU is seen to be imperative for the long term development and installation of "rational" Picture Archiving and Communications Systems (PACS). A "rational" PACS being one with true multivendor, peer to peer, interconnectivity.